Final answer:
Nitrogen is the substance not transferred by the alveoli, as they primarily facilitate the exchange of oxygen and carbon dioxide between the lungs and blood.
Step-by-step explanation:
The substance not transferred by the alveoli is nitrogen. In the context of respiration, the alveoli are responsible for the exchange of oxygen and carbon dioxide between the lungs and the blood. Oxygen is diffused into the bloodstream and is transported to tissues, while carbon dioxide diffuses out of the blood into the alveoli to be expelled from the body. Water vapor is also exchanged to a degree because the alveoli work to humidify incoming air. However, the overwhelming majority of inhaled nitrogen is not transferred by the alveoli, but rather is exhaled.